How to run command prompt in background using Node.js Child process?

Question

On button click I can open a command prompt using Node.js child process.

var child_process = require('child_process');

 let command = `start cmd.exe /K "cd /D c:/Users && java"`

 let process = child_process.spawn(command, [], { shell: true }) //use `shell` option

using above code I can open a command prompt and run Java command at specified location.

Now my question how can I do same process in background without opening command prompt (cmd) ?

Hi @Vishal-Lia can you tell me more specific like how can I run in background using exec ? — JEETHESH KARKERA
– JEETHESH KARKERA, Commented Jul 12, 2019 at 6:12

darklightcode · Accepted Answer · 2019-07-12 09:53:07Z

2

Spawn has the cwd (Current Working Directory) option which you can point to open up the process.

var child_process = require('child_process');

let bin = 'java';
let cliArgs= ['-version'];
let options = {
  spawn: true,
  cwd: 'c:/Users'
}

let command = child_process.spawn(bin, cliArgs, options ) //use `shell` option

command.stdout.on('data', (data) => {
  console.log(`stdout: ${data}`);
});

command.stderr.on('data', (data) => {
  console.log(`stderr: ${data}`);
});

command.on('close', (code) => {
  console.log(`child process exited with code ${code}`);
});

edited Jul 12, 2019 at 9:53

answered Jul 12, 2019 at 7:33

darklightcode

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3 Comments

JEETHESH KARKERA Over a year ago

Thank you for the answer. If I use above code I'm getting following error ` let arguments = ['-version']; ^^^^^^^^^ SyntaxError: Unexpected eval or arguments in strict mode`

JEETHESH KARKERA Over a year ago

Thank you it worked with little modification. I removed let arguments = ['-version']; and added let bin = 'java -version'; Also passed [] in let command = child_process.spawn(bin, [], options )

darklightcode Over a year ago

I updated my code, "arguments" is a javascript object inside functions. Since you were using strict mode the error was triggered because it's not defined anywhere. I just had to rename it. Try with the renamed variable again, it's not good practice to use the arguments along with the executable as you mentioned this let bin = 'java -version';. Your CLI arguments should be in the 2nd parameter, the array, which will be .join-ed with a space before executing the full command.

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